Red Hat: Security update for X11 video driver

The xorg-x11-drv-qxl package provides an X11 video driver for the QEMU QXL video accelerator. A flaw was found in the way the host’s qemu-kvm qxl driver and the guest’s X.Org qxl driver interacted when a SPICE connection terminated. A user able to initiate a SPICE connection to a guest could use this flaw to make the guest temporarily unavailable or, potentially (if the sysctl kernel.softlockup_panic variable was set to “1” in the guest), crash the guest.